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United States Patent |
5,714,656
|
Ciali
,   et al.
|
February 3, 1998
|
Bases for lubricating oils and process for their preparation
Abstract
Composition of lubricating oil which comprises: a) a greater portion of
synthetic lubricating component or a mixture of synthetic lubricating
component and a mineral base for lubricating oils, the synthetic
lubricating component being prepared by the oligomerization and subsequent
hydrogenation and the possible removal of low-boiling by-products, of a
composition of olefins basically consisting of:
1) a mixture of n-olefins having a content of olefins from C.sub.14 to
C.sub.17, preferably from C.sub.15 to C.sub.16, of at least 80%,
preferably greater than 85%,
2) alpha olefins from C.sub.15 to C.sub.17, preferably basically C.sub.16,
the content of the alpha olefin (2) being from 5 to 25% by weight,
preferably from 10 to 20%, with respect to the sum of (1)+(2).
Inventors:
|
Ciali; Massimo (Milan, IT);
Ontano; Rosanna (Milan, IT);
Radici; Pierino (Turate, IT);
Marcotullio; Armando (S. Donato Mil.SE, IT);
D'Antona; Paolo (Assago, IT)
|
Assignee:
|
Condea Augusta S.P.A. (Milan, IT)
|
Appl. No.:
|
744214 |
Filed:
|
November 5, 1996 |
Foreign Application Priority Data
| Nov 30, 1995[IT] | MI95A2501 |
Current U.S. Class: |
585/10; 208/19; 585/12; 585/13 |
Intern'l Class: |
C10M 101/00; C10M 105/04 |
Field of Search: |
208/19
585/10,12,13
|
References Cited
U.S. Patent Documents
3926579 | Dec., 1975 | Rossi et al. | 585/13.
|
3965018 | Jun., 1976 | Heilman et al. | 208/19.
|
4132663 | Jan., 1979 | Heilman et al. | 44/459.
|
4218330 | Aug., 1980 | Shubkin | 585/13.
|
4876017 | Oct., 1989 | Trahan et al. | 252/8.
|
5146021 | Sep., 1992 | Jackson et al. | 585/12.
|
5146022 | Sep., 1992 | Buchanan et al. | 585/12.
|
5171909 | Dec., 1992 | Sanderson et al. | 585/12.
|
5364994 | Nov., 1994 | Scharf | 585/13.
|
5593463 | Jan., 1997 | Gambini et al. | 585/10.
|
5602086 | Feb., 1997 | Le et al. | 585/10.
|
Primary Examiner: Medley; Margaret
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Claims
We claim:
1. A lubricating oil composition, consisting essentially of an oligomer
synthetic lubricating oil base, which is prepared by oligomerizing and
subsequentially hydrogenating an olefin mixture, comprising:
1) a mixture of n-olefins having a content of olefins from C15 to C16 of at
least 80%, and
2) C16 .alpha.-olefins,
wherein the content of said .alpha.olefins (2) are from 10 to 20% by weight
with respect to the sum of(1) and (2) and
further wherein said lubricating oil composition has a viscosity at
30.degree. C. of not more than 2300 cP.
2. The lubricating oil composition of claim 1, wherein the mixture of
n-olefins has a content of at least 85%.
3. The lubricating oil composition of claim 1, which further comprises a
mineral base.
4. The lubricating oil composition of claim 3, wherein said mineral base is
selected from the group consisting of paraffinic, naphthenic and mixed
paraffinic-naphthenic mineral bases.
5. The lubricating oil composition of claim 1, which further comprises an
additive selected from the group consisting of pour point depressants,
viscosity index improvers, detergent-dispersants, corrosion inhibitors,
oxidation inhibitors, wear inhibitors, antifoaming agents and friction
modifiers.
6. The lubricating oil composition of claim 1, wherein the preparation of
said synthetic lubricating component further comprises removing
low-boiling by-products.
7. The lubricating oil composition of claim 1, wherein the oligomerization
is carded out at between about 0.degree. C. and 180.degree. C.
8. The lubricating oil composition of claim 7, wherein the oligomerization
is carried out at between about 20.degree. C. and 90.degree. C.
9. The lubricating oil composition of claim 1, wherein the oligomerization
is effected in the presence of adducts of AlCl.sub.3 with esters,
complexes of BF.sub.3 with alcohols, organic or inorganic acids, or
dispersions of AlCl.sub.3 as supports of silica or alumina.
10. The lubricating oil composition of claim 9, wherein the oligomerization
is effected in the presence of BF.sub.3 and an inorganic acid selected
from the group consisting of sulfuric acid, phosphorous acid and
phosphoric acid.
11. The lubricating oil composition of claim 1, wherein said hydrogenation
is effected at from 10-40 kg/cm.sup.2 of pressure at temperatures of
150.degree.-240.degree. C. using Pd or Ni as a catalyst.
12. The lubricating oil composition of claim 11, wherein said hydrogenation
is effectd at from 20-25 kg/cm.sup.2 of pressure at a temperature of
170.degree.-180.degree. C. using Pd/C at 10% of Pd as a catalyst.
Description
The present invention relates to bases for lubricating oils and the process
for their preparation.
The possibility of obtaining bases for lubricating oils by the
oligomerization and subsequent hydrogenation of internal olefins is
described in literature.
In particular IT-A-20106 A/80 describes the oligomerization of internal
olefins, particularly internal olefins having a number of carbon atoms of
between 12 and 20, preferably between 15 and 18.
The above oligomerization takes place in the presence of suitable
catalysts, particularly adducts of AlCl.sub.3 with esters, complexes of
BF.sub.3 with alcohols, organic and inorganic acids. As shown from mass
spectrometry and bromometric titrations, the oligomers thus obtained
generally have a double bond for each molecule. The oligomerization
usually produces a mixture of dimers and trimers, the higher oligomers
generally being less than 5-10%. The unsaturated oligomers are then
hydrogenated in the presence of catalysts well known to experts in the
field.
The products thus obtained, without any possible light products, are called
PIO (poly internal olefins).
The main use of the above PIO, particularly those deriving from
compositions mainly consisting of C15-C16 n-olefins, is as a base for
synthetic or semi-synthetic lubricating oils.
A composition has now been found which, with the same viscosity at a high
temperature, improves the already good viscosity characteristics at room
temperature of the above PIO.
In accordance with this, the present invention relates to a composition of
lubricating oil which comprises:
a) a greater portion of synthetic lubricating component or a mixture of
synthetic lubricating component and a mineral base for lubricating oils,
the synthetic lubricating component being prepared by the oligomerization
and subsequent hydrogenation and the possible removal of low-boiling
by-products, of a composition of olefins basically consisting of:
1) a mixture of n-olefins having a content of olefins from C.sub.14 to
C.sub.17, preferably from C.sub.15 to C.sub.16, of at least 80%,
preferably greater than 85%,
2) alpha olefins from C.sub.15 to C.sub.17, preferably basically C.sub.16,
the content of the alpha olefin (2) being from 5 to 25% by weight,
preferably from 10 to 20%, with respect to the sum of (1)+(2).
The term n-olefins means olefins in which the double bond is not solely
present in position 1,2 (like alpha-olefins), but on the other hand is
statistically distributed along the whole chain.
These n-olefins are preferably obtained with the process called PACOL-OLEX
by the dehydrogenation of n-paraffins.
The composition of n-olefins (1) usually contains impurities mainly
consisting of paraffins, aromatics and isoparaffins, in a quantity however
which is generally less than 10%, usually less than 8%.
The mixture of n-olefins (1) and alpha-olefins (2) will hereinafter be
called olefins, for the sake of clarity.
As far as the oligomerization reaction is concerned, this can be carried
out (see IT-A-20106 A/80) in the presence of adducts of AlCl.sub.3 with
esters or complexes of BF.sub.3 with alcohols, organic and inorganic
acids, dispersions of AlCl.sub.3 on supports consisting of silica or
alumina. It is preferably however to use complexes of BF.sub.3 with
inorganic acids, preferably selected from sulphuric acid, phosphorous
acid, phosphoric acid. In a preferred embodiment the weight ratio BF.sub.3
/olefins is from 1.2 to 2.2, preferably from 1.4 to 1.7, grams of BF.sub.3
per 100 grams of olefins; the ratio between inorganic acid and olefins is
from 0.2 to 0.6, preferably from 0.3 to 0.5, grams of acid per 100 grams
of olefins.
The oligomerization reaction is carried out at a temperature of between
0.degree. C. and 180.degree. C., preferably between 20.degree. C. and
90.degree. C., even more preferably between 50.degree. and 70.degree. C.
At the end of the oligomerization reaction it is preferable to neutralize
the reaction raw product.
The reaction products consist of oligomers of the starting olefins, mainly
dimers and trimers with small quantities of tetramers and pentamers, as
shown by gaschromatographic analysis together with mass sepctrometry.
With respect to the hydrogenation step, this can be carried out in the
presence of suitable catalysts and under the usual conditions (in
particular of pressure and temperature) for the hydrogenation of olefins.
The hydrogenation reaction is preferably carried out in the presence of
catalysts based on Pd or Ni, as such or supported, at a temperature of
between 150.degree. and 240.degree. C. and a hydrogen pressure of between
10 and 40 kg/cm.sup.2.
According to the oligomerization process described above, a conversion
degree of the starting olefins of between 70 and 90% is usually obtained,
making it necessary to have a step for eliminating the light fractions,
normally by distillation.
This step can be carried out at the end of the oligomerization reaction or
after the subsequent hydrogenation reaction, preferably after the
hydrogenation step.
The bases for lubricating oils thus prepared can be used as a main
component for synthetic lubricants or mixed with conventional mineral
bases, together, obviously, with smaller quantities of additives.
The conventional mineral bases, which can be possibly used with the
oligomerization and hydrogenation product of the present invention, can be
of the paraffinic, naphthenic, or mixed paraffin-naphthenic type. In
addition they can be distillates or distillation residues, or synthesis
products.
In the case of the formulation of lubricants for engines, hydrocarbon
fractions basically consisting of distillates of the paraffinic type are
preferable.
Typical synthetic lubricating bases which can possibly be mixed with the
composition of products of the present invention are esters of
monocarboxylic aliphatic acids with polyhydroxylic alcohols, such as
trimethylol propane and pentaerythrol; esters of diacids with
monofunctional alcohols; synthetic hydrocarbons; polyglycols; thiols;
siliconic fluids; polyphenyl ethers; thioethers.
As is known to experts in the field, compositions of lubricating oil
contain additives suitable for improving the performance of the synthetic
component of the present invention or of the mixture of the above
synthetic component with other conventional mineral or synthetic bases.
The additives can therefore be the usual pour point depressants; viscosity
index improvers; detergents-dispersants; corrosion, oxidation and wear
inhibitors; antifoaming agents, friction modifiers, etc.
The selection of additives to be included in the finished oil and relative
quantities depend on the use and performances desired.
As an example, viscosity index improvers and pour point depressants are
contained in the finished oil in a quantity of between 0.01 and 15% by
weight; detergents-dispersants (typical examples of which are
succinimides) in a quantity of between 0.1 and 15% by weight; corrosion,
oxidation and wear inhibitors in a quantity of between 0.01 and 3% by
weight; antifoaming agents between 10 and 1000 ppm.
Many other additives with different functions can be used in preparing the
final formulates. Many of these components are listed in U.S. Pat. No.
3,864,270, U.S. Pat. No. 4,169,799, U.S. Pat. No. 4,194,981 and U.S. Pat
No. 4,253,980.
The following examples provide a better understanding of the present
invention.
EXAMPLES
1--Composition of n-Olefins
The substrate subjected to oligomerization and hydrogenation consists of:
(1) a mixture of C15-C16 n-olefins; (2) C16 .alpha.-olefin.
The mixture of C15-C16 n-olefins has the following composition
(Gaschromatographic analysis on a capillary column):
n-Paraffins: 4.04% by weight (of which C15=2.81%, C16=1.07%, C17=0.16%);
n-Olefins: 92.68% by weight (of which C15=70.68%, C16=19.55%, C17=2.45%);
Aromatics+isoparaffins: 3.28%.
The C16 alpha-olefin is a product having a content of alpha-olefins of 94%.
Of these alpha-olefins, the content of C16 alpha-olefin is 88%, the
remaining 12% consisting of C14 and C18 alpha-olefins.
1--Synthesis of the Bases
The synthesis basically consists of an oligomerization step of the olefins,
followed by neutralization and washing of the BF.sub.3.acid complex, a
hydrogenation step of the oligomers thus obtained and then a stripping
step of the light products.
For the oligomerization a 1 liter Brignole autoclave in AISI 316 is used,
equipped with a magnetic stirrer, 4 valves of which one is a plunged pipe,
a thermometric hole, a thermocouple and digital indicator for measuring
the temperature, a manometer able to measure up to 12 kg/cm.sup.2.
For the hydrogenation of the oligomers a 1-liter Engeneering autoclave in
Hastelloy C is used, equipped with a magnetic stirrer, 4 valves,
thermometric hole, thermocouple, digital indicator for measuring the
temperature, burst disk calibrated at 30 bars and manometer able to
measure up to 25 kg/cm.sup.2.
For the stripping, or the distillation of the light products formed during
the reaction and non-oligomerized products, a 1-inch adiabatic column (of
the Oldershaw type) with 5 plates is used. The operation is carried out at
reduced pressure (about 0.5-1 torr) and with a final temperature at the
head of about 170.degree.-180.degree. C. until the head products have been
completely removed, verified by gaschromatographic analysis on both the
head products and residual tail products in the boiler.
The oligomerization of the olefins is carried out by charging the mixture
of olefins and inorganic acid into the autoclave with the ceiling open.
All the tests, including the comparative ones, were carried out with an
almost constant ratio BF.sub.3 /olefins (from 1.43 to 1.65 grams of
BF.sub.3 per 100 grams of olefinic composition) and with a constant ratio
acid/olefins (0.40 grams of acid per 100 grams of olefins).
A seal test is carried out with nitrogen and the autoclave is flushed four
times at 5 kg/cm.sup.2, again with nitrogen.
The nitrogen is then degassed and BF.sub.3 is fed from a previously weighed
cylinder. The stirring is activated (760 rpm) and the temperature is
brought to 60.degree. C. After the preset reaction time the BF.sub.3 is
degassed and sent to appropriate collection traps of NaOH+Ca(OH).sub.2 ;
flushing is repeatedly carried out with nitrogen and the contents of the
autoclave is discharged.
The oligomers are neutralized with an aqueous solution of sodium carbonate
with the pH value under control and subsequently washed with distilled
water.
The olefinic oligomers thus prepared are hydrogenated at 20-25 kg/cm.sup.2
of pressure with temperatures of 170.degree.-180.degree. C. using Pd/C at
10% of Pd as catalyst. The reaction is carried out at 1500 rpm of stirring
for 7-8 hours until the complete reduction of the starting oligomers. The
catalyst is charged in a ratio of 4% with respect to the charge to be
hydrogenated.
The oligomers thus hydrogenated are filtered from the catalyst and
distilled.
Gaschromatographic analyses are carried out on the weighed distillate and
boiler residue and the residue is rheologically characterized.
3--Rheological Characterization
The rheological characterization of the bases is carried out at
temperatures of 40.degree. and 100.degree. C. using a series of
capillaries of the Cannon Fenske type and a thermostatic bath with a
control to a hundredth of degree centigrade.
For the Pour Point and viscosity at -30.degree. C. measurements a
rotational rheometer is used with a strain rate range applied is 0.1-1000
sec.sup.-1 and the relative viscosity value indicated refers to the value
of the flow curve at 100 sec.sup.-1. For the Pour Point measurements a
frequency of 1 Hz is used together with an amplitude of 0.001 mrad and a
temperature increase of 1.degree. C./min.
The results of the tests and analyses are shown in table 1. Examples 3C/95
and 5C/95 are comparative examples as they are carried out with 30% and 0%
of alpha-olefin respectively.
TABLE 1
______________________________________
Rheological characterization
100.degree. C.
40.degree. C.
-30.degree. C.
P.P.
Test % .alpha.C16
Yield (cSt) (cSt) (cP) I.V. (.degree.C.)
______________________________________
1/95 10 87.0 5.75 29.59 2150 140 -35
4/95 15 85.6 5.87 30.74 2300 138 -33
2/95 20 86.1 5.75 29.64 2200 139 -32
3C/95 30 88.0 5.86 30.51 2550 139 -26
5C/95 0 83.0 5.69 30.59 2760 124 -45
______________________________________
The results of table 1 clearly show the advantages, in terms of viscosity
at -30.degree. C., which can be obtained with the compositions containing
from 10 to 20% of C16 alpha-olefin. In fact the viscosity values at
100.degree. C. are comparable, whereas the viscosities at -30.degree. C.
are improved.
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